In December 1979, the Su-27 was officially accepted by the military for governmental testing. But it was a different version of aeroplane that was put into series production. Comprehensive analysis of the performance of the Su-27 performance compared to similar Western models, semi-realistic simulation of air combat and actual data obtained during the first flights of the prototype failed to confirm the expected air-superiority of the Su-27. Such a result was due to a number of reasons, the major ones being underestimation of the actual performance capabilities of the F-15, and on the serious excess weight of the Su-27 through failure to meet the weight restrictions for the systems and equipment design as well as the underperformance of the AL-31F engines revealed during their bench testing. To meet the PR targets and achieve a guaranteed result in the plane's basic role, on the initiative of Chief Designer M.P. Simonov, and approved by General Designer Ye.A. Ivanov, the Bureau developed a plan of actions to:
- introduce tight control of weight,
- decrease drag,
- increase the lift properties of the wing to adapt it to different flight modes,
- improve the plane's roll control.
- adopt a tapered wing design with a leading-edge flap and flaperon,
- move the aircraft accessories box onto the back of the engine, which made it possible to "hide" it in the centre-wing airflow-shadow and reduce the plane's maximum cross-section,
- adopt a new functional solution for main landing gear retraction based on a slanting hinging axis and a lock to fix the gear leg on the engine housing,
- move the fins from the engine nacelles to the fuselage beams to improve their rigidity and the fin performance.
Taken together, all the modifications were incorporated in the configuration that became known as T-10S ("S" being short for "production" in Russian). General Designer Ye.A. Ivanov made a difficult decision to have the aircraft redesigned. The root of the problem was that the engineering follow-up involved suspending the series production already in progress and initiating a new major process to put the project into production, i.e., failure to meet the production targets.
The Design Bureau's position was strongly opposed by the management of MAI and the production plant, but it was supported by deputy minister I.S. Silayev. As a result, a decision to this effect was made in January 1978, and the Design Bureau started work on detailed design based on the T-10S configuration. Between 1979 and 1981, the Su-27 project at the Design Bureau was headed by A.A. Kolchin, and since 1981, the aeroplane's Chief Designer has been A.I. Knyshev.
The first Su-27 prototype in production configuration, T10-7, was accepted for flight testing in the spring of 1981, its first flight performed by V.S. Ilyushin on 20th April 1981. In 1982, the Komsomolsk-on-Amur plant started mass production. The first series Su-27 was flight tested at the plant on 1st June 1982, the plane having been taken off the ground for its first flight by the design bureau's test pilot A.N. Isakov. Governmental integration tests of the Su-27 were completed in December 1983.
The test results confirmed the extremely high APC of the new aeroplane. When brought together, the modifications produced a synergetic effect on the T-10S: the resulting plane demonstrated superior flight performance, leaving behind all the rivals in its class.
The testing of the Su-27 under a variety of programs continued for several years longer. The Su-27 was officially put into service by a decree of the government of 23rd August 1990 after all the major faults identified during the tests had been remedied. By that time, Su-27 had been in service for 5 years. The first pilots at combat units to receive the Su-27 in June 1985 were the aviators of the 60th FAR in the Far Eastern MD (Dzemghi). By 1989, Su-27 aeroplanes were in service in 16 combat units of the Air Forces and ADF of the USSR. According to the command personnel and pilots of the transition units, despite the fact that in terms of scope and complexity the systems and weapons the plane was far superior to all aircraft of the previous generation, Su-27 transition training was quite straightforward and problem-free, with the plane proving quite easy to master for average pilots.
|Join the GlobalSecurity.org mailing list|